Dear forum participants,
A requirement to detect and uniquely identify an organism developed using biotechnological tools may be connected to its regulatory status. Where the organism is regulated as an LMO/GMO, developers may be required to develop methods that enable the organism to be detected in trade once it is commercialised, e.g. in bulk shipments of grain.
However, in the context of the protocol, these methods are only relevant for LMOs are likely to cause adverse effects on the conservation and sustainable use of biological diversity, taking also into account risks to human health.
Methods used in the regulatory field are often validated PCR-based methods, although protein-based methods are also a valid and much more economical approach. Methods must also conform with certain performance criteria as set out in the Codex guideline CAC/GL 74-2010, and with regulatory requirements, and be practically feasible for use with bulk commodities. Such PCR and protein-based methods and links to Certified Reference Material providers are routinely posted in the database:
http://www.detection-methods.com. Where organisms are not within the scope of LMO/GMO regulation in a country or trading block, there should not be a requirement for a specific detection method to uniquely identify them, as expressed by Apichart Vannavichit, #10016. For crops developed using genome editing, there are currently a range of approaches to their regulation, with certain applications regulated as LMOs/GMOs and therefore detection methods may or may not be required. For such organisms, the ability to develop sufficiently sensitive detection methods depends on the type of edit. Where the edit involves the incorporation of a DNA sequence of sufficient size for the design of PCR primers (e.g. a gene cassette), PCR-based detection methods can be developed – this is same approach used for the development of detection methods for currently commercialized LM/GM crops.
The development of detection methods is less straightforward where applications of genome editing in plants have comparable outcomes to conventional breeding approaches. While it may be technically feasible to detect small DNA sequence changes in single plants and seeds, detection in bulk seed and grain samples will be much more difficult, even impossible, despite claims to the contrary. The currently used methods are likely to be stretched to their technical limits, prone to errors and misinterpretation due to false positives, and they are unlikely to meet the established performance criteria applied to LM/GM crop detection methods. The use of screening methods commonly used by a number of participants in this forum to detect LM/GM crops (e.g. #9974 #9990, #9992, #9997, #10012) will not be practical, as each edit is unique, thus leading to a high cost of detecting and diversion of precious resources that could be used for more important societal issues to try to detect an essentially safe product through the application of 10’s and eventually hundreds of separate assays.
We support the position of Pr Stephen Ghogomu, Cameroon in post #9981 in Topic 2, regarding the inability of current analytical methods to “distinguish between the natural and the synthetic/chemical counterparts”. While it may be technically feasible to detect small DNA sequence changes in single plants and seeds, it is not possible to distinguish or determine how a specific change arose during the breeding process – as a result of the use of a genome editing tool, conventional mutagenesis, or spontaneous mutations – because their outcomes are similar or the same. This was also the conclusion of the European Network of GMO Laboratories (ENGL, 2019) report, and it adds a further complication to the detection of organisms developed using certain applications of genome editing in bulk shipments.
Claims by Bertheau (2019) to be able to distinguish targeted single base changes from those that occur spontaneously in plants due to claims that ‘plant genomes are stable’ are inaccurate. The plasticity of plant genomes is well-documented in the scientific literature, with point mutations, insertions, and rearrangements commonplace (e.g. Arber 2010; Custers et al 2019; Schnell et al 2015; Weber et al 2012). Moreover, the Central Committee on Biological Safety (ZKBS), a voluntary expert panel responsible for evaluating GMOs sponsored by the German Federal Office of Consumer Protection and Food Safety, has rebutted these claims stating: “The option suggested by Bertheau to retroactively identify an edited base within a plant genome and the technique used to generate it is non-existent. The proposed methods are not based on current scientific knowledge and furthermore involve highly variable biological parameters (like epigenetic changes) that are no reliable base for identification.” The ZKBS also referred to the conclusion of the ENGL report: “the report of the Joint Research Centre (JRC) of the European Commission and the European Network of GMO Laboratories (ENGL) that the hints from characterization of a plant that point towards genome editing as quoted by Bertheau are not sufficient to identify which technique was initially applied.”
References cited:
-- Arber W (2010) Genetic Engineering Compared to Natural Genetic Variations, New Biotechnology 27: 517-521.
-- Bertheau Y (2019). In: Encyclopedia of food chemistry (p. 320-336). DOI: 10.1016/B978-0-08-100596-5.21834-9
-- CAC/GL 74-2010 Guidelines on performance criteria and validation of methods for detection, identification and quantification of specific DNA sequences and specific proteins in foods. Available at:
http://www.fao.org/fileadmin/user_upload/gmfp/resources/CXG_074e.pdf.
-- Custers R, Casacuberta JM, Eriksson D, Sági L, Schiemann J (2019) Genetic alterations that do or do not occur naturally; consequences for genome edited organisms in the context of regulatory oversight, Frontiers in Bioengineering and Biotechnology 6: 213. doi:10.3389/fbioe.2018.00213.
-- European Network of GMO Laboratories (ENGL) report endorsed by the ENGL Steering Committee, 26 March 2019: “Detection of food and feed plant products obtained by new mutagenesis techniques”.
-- On the Identifiability of Genome Editing in plants, September 2019 – ZKBS-commentary on Y. Bertheau (2019),
http://www.zkbs-online.de/ZKBS/EN/01_Aktuelles/ZKBS-commentary%20on%20Y.%20Bertheau%20(2019)/ZKBS-commentary%20on%20Y.%20Bertheau%20(2019)_basepage.html viewed on November 6, 2019.
-- Schnell J, M Steele, J Bean, M Neuspiel, C Girard, N Dormann, C Pearson, A Savoie, L Bourbonnière, P Macdonald (2015) A comparative analysis of insertional effects in genetically engineered plants: consideration for pre-market assessments, Transgenic Research 24: 1-17.
-- Weber N, C Halpin, LC Hannah, JM Jez, J Kough, W Parrott (2012) Crop genome plasticity and its relevance to food and feed safety of genetically engineered breeding stacks, Plant Physiology 160: 1842-1853.
